mesa: 18.2.5 -> 18.2.6

https://www.mesa3d.org/relnotes/18.2.6.html

pkgs/development/libraries/mesa/default.nix

@@ -67,7 +67,7 @@ let
 in
 
 let
-  version = "18.2.5";
+  version = "18.2.6";
   branch  = head (splitString "." version);
 in
 
@@ -81,7 +81,7 @@ let self = stdenv.mkDerivation {
       "ftp://ftp.freedesktop.org/pub/mesa/older-versions/${branch}.x/${version}/mesa-${version}.tar.xz"
       "https://mesa.freedesktop.org/archive/mesa-${version}.tar.xz"
     ];
-    sha256 = "0wrbdk988mh42bbpicf5knx5pdqs3xp05s71alqkbr9j523k4b5i";
+    sha256 = "04nwxykmc80gicmal0zkk8is34rmbqawmfckirqhrps9h97zmfly";
   };
 
   prePatch = "patchShebangs .";